Costco Wholesale Corp. has begun requiring fresh produce and beef vendors to test for a wide range of E. coli strains, including O104:H4 that caused a massive outbreak tied to sprouts in Europe.

“We’ve had test and hold for ready-to-eat vendors for four to five years,” Craig Wilson, Costco’s food safety director, told The Produce News July 20. “This is the next step in the evolution.”

Walmart announced earlier this year that it would require beef vendors to test for more strains of E. coli, and Costco widened the testing to fresh produce, starting last month.

E. coli O157:H7 is the most common strain found in U.S. beef and also has been linked to produce-related outbreaks. But health officials have been concerned with other strains, including the E. coli O104:H4 that caused more than 40 deaths and 800 people to suffer hemolytic uremic syndrome across Europe.

The European Food Safety Authority traced the outbreak to sprouts and suspects that an Egyptian sprout seed supplier was the likely culprit.

Costco’s decision to move ahead with testing meat and produce for additional non-O157:H7 strains comes as the U.S. Department of Agriculture is considering a petition by Seattle-based law firm Marler Clark that would render six E. coli strains legal adulterants in meat.

Consumer advocates have been pressing the USDA to require the meat industry to test for more E. coli strains and challenging the White House to release a USDA rule on the issue. Sen. Kirsten Gillibrand (D-NY), meanwhile, introduced a meat safety bill (S.1157) last month that would require wider pathogen testing in ground beef plants.

Mr. Wilson said Costco had been testing the new specification for produce and beef vendors for months, but “formalized” the requirement in June.

“Why wouldn’t you do this to protect the public?” Mr. Wilson asked. It’s the right thing to do.”